Studies of hadronic B decays with early LHCb data

1. Studies of hadronic B decays with early LHCb data Aurélien MARTENS (LAL – Univ. Paris Sud 11 – Orsay) On behalf of the LHCb Collaboration Hadronic B decays @ LHCb - Kruger2010

2. γ and the current status of the CKM matrix Full fit : CKMfitter : γ = (67.2 ± 3.9)° UTfit : γ = (65.6 ± 3.3)° Loops Loop constraints are more precise than tree ones. Good agreement with some small tension CKMfitter Group (J. Charles et al.), EPJC41, 1-131(2005), Bona et al. (UTfit Collaboration), JHEP 0507 028(2005) Direct measurements : CKMfitter : γ = (71 ± 23)° UTfit : γ = (78 ± 12)° Trees Interest in more precise direct measurements Hadronic B decays @ LHCb - Kruger2010

3. Introduction : γ extraction at LHCb • Current direct determination of γ is mainly dominated by Dalitz measurements in BDK, DKshh • There are two direct ways to access the CKM angle γ • In tree diagrams : B  DX decays • Time integrated • Time dependent • In loop diagrams : B  hh or hhh charmless decays • Assumes U-spin to extract γ • All of these accessible with unprecedented precision at LHCb • Precise measurements of direct, mixing induced and interferences induced CPV • Measurements within Standard Model channels and new physics polluted ones • uncover new physics contributions in loops • by comparing it with trees • By comparing with global fit Roadmap for selected key measurements of LHCb, arχiv:0912.4179v2 Hadronic B decays @ LHCb - Kruger2010

4. Time integrated γ from trees e-iγ Colour Allowed Cabibbo Favoured Colour Suppressed • An ideal Standard Model candle • Tree diagrams  no contribution from new physics in B decays • Neglect D mixing : dominant bias but still negligible (~1°) • Neglect CPV in D decays : negligible contribution • Absolute relative theoretical uncertainty (EW corrections) : Δγ/γ~ 10-6 ADS [PRL 78 3257(1997); PRD 63 036005(2001)], GLW [PLB 253 483(1991); PLB 265 172(1991)], GGSZ [PRD 68 054018(2003)] bu and bctransitions interfere D0’s reco. in the same final state : CP eigenstate KK, ππ[GLW] 2 bodies & al. Kπ, Kππ0, K3π[ADS] Dalitz Kshh [GGSZ] Extentions : D0Kπ Dalitz analysis with higher statistics BsDΦ integrated-untagged measurment ADS : CLEOc constraints on D decay Hadronic B decays @ LHCb - Kruger2010

5. Time dependent γ from trees • An additional information from time dependent measurements • Measure γ+ΦM  need an external model independent measurement of the mixing phase • Benefits from non vanishing lifetime differences [ for Bs,  for Bd] e-iγ MIXING Aleksan & al. [ZPC 54 653(1992)], Dunietz & al. [PRD 37 3186(1988) ; 39 3515E(1989)], Dunietz [PLB 427 179(1998)] Simultaneous U-spin based extraction : resolve 8-fold ambiguities (degenerated at low statistics) in BdD+π- Hadronic B decays @ LHCb - Kruger2010

6. γ from loops • Inclusive Bhh or hhh analyses • bu involved in many (2,3)-bodies charmless B decays • Less particles in the final state  more efficient trigger and reconstruction  Examples of contributing and interfering diagrams (more in backup) Fleischer [PLB 459(1999) 306 arXiv:9903456, EPJ C52(2007) 267 arXiv:0705.1121] BR 10-610-5 Upper limits 10-6 Hadronic B decays @ LHCb - Kruger2010

7. LHCb in a nutshell The Challenge: precise rare decays and time-dependent CP asymmetries in a high background environment. Needs excellent vertexing, p reconstruction, particle-ID Tracking Stations Trigger Tracker See Plenary by O. Steimkampf Calorimeters The LHCb Detector at the LHC [JINST 3 S08005] Muon System VErtexLOcator, PileUp RICHES: PID: K, separation Hadronic B decays @ LHCb - Kruger2010

8. Trigger • The bottleneck : • Bandwidth and rate limitations • Already high (3.6 GeV) ET hadronic triggers HLT1 : - Build a ‘good’ track from any L0  Recover some efficiency for hadronic triggers • HLT2 : • Inclusive Topological Trigger : • Build a B using 2,3,4 tracks • Compensate for missing pT Hadronic B decays @ LHCb - Kruger2010

9. Analysis requirements : PID Hadronic B decays  intensive use of PID in any analysis See talk by A. Contu Performance is close to MC expectations Lifetime and Tagging performance studies also under progress Hadronic B decays @ LHCb - Kruger2010

10. ~35pb-1 Observations : time integrated γ trees ~35pb-1 ~35pb-1 BD(KK)π 1035 ± 54 BD(Kπ)ρ0 74 ± 11 ~35pb-1 Clean hadronic B signals observed reasonably in agreement with expectations BD(Kπ)K 444 ± 30 Wait for full 2010 run reprocessing to observe BDK with DKK BD(Kπ)ρ 74 ± 11 First observation of pure colour suppressed hadronic B decays in a hadron collider (?) Expect 15 to 50 BsD0K*0 in the full 2010 reprocessing Hadronic B decays @ LHCb - Kruger2010

11. Prospects : time integrated γ trees ADS LHCb 1fb-1 @ √s=7TeV : Competitive measurements with current dominating measurements Current status on the measurementof asymmetries Arχiv:1007.0504, PRD 81, 031105(R)(2010) + preliminary results @ CKM 2010 • possiblefirst results from LHCb@ Winter 2011 conferences : • ACP+andRCP+competing with CDF • ratios ofBR(BDK)/BR(BDπ) • First observation ofBsD0K*0 and BR(BsD0K*0)/BR(BdD0ρ0) ~15° LHCb combined sensitivity on time integrated γ in 2011 Hadronic B decays @ LHCb - Kruger2010

12. Observations : time dependent γ trees ~35pb-1 ~35pb-1 B+D0πππ & B0D+πππ BsDs(Φπ)π Six body final states observed ! BsDsπππ also seen Hadronic B decays @ LHCb - Kruger2010

13. Prospects : time dependent γ trees B factories legacy Fleischer, Serra, Tuning [Arχiv:1004.3982v3] http://www.slac.stanford.edu/xorg/hfag/ • possiblefirst results from LHCb@ Winter 2011 conferences : • Measurements of ratio of BR(B0DK)/BR(B0Dπ) • Upper limits on BsD(K,π) • First observations ofD(s)(Kππ) and best measurements of D(s) (πππ) • fd/fs from N(B0DK)/N(BsDsπ) ~15° statistical sensitivity on time dependent γ in 2011 Hadronic B decays @ LHCb - Kruger2010

14. Observations : γ loops MC expectations Bd Bs Raw asymmetries already visible by eye !  work ongoing on proper estimates Hadronic B decays @ LHCb - Kruger2010

15. Prospects : γ loops CDF, [N PB (Proc. Suppl.) 170 (2007) 39–45] http://www.slac.stanford.edu/xorg/hfag/ • possiblefirst results from LHCb@ Moriond 2011 : • Measurement of BR(BsKπ)/BR(BdKπ) • ACPmeasurements competitive with CDF results ~15° sensitivity on γ loops for LHCb by fall 2011 Hadronic B decays @ LHCb - Kruger2010

16. Summary • LHCb is performing well and is already able to observe hadronic B decays • 10-5 and 10-6 hadronic decays are observed or about to be so • Discoveries of new expected Bs decay modes hopefully for Winter conf. • Raw asymmetries observed in some channels • Hopefully calibrated by Winter conf. to produce first CPV results • Wait for even more exciting data taking periods in 2011 • γ sensitivity is going to be of the order of 15° in loops AND trees • γ sensitivity of 15° both in time independentAND time dependenttrees • Competitive with existing measurements LHCb will be competitive with CDF results LHCb will improve our knowledge on γby the end of 2011 Hadronic B decays @ LHCb - Kruger2010

17. Thank you Have fun : find the 4 PV’s ! Hadronic B decays @ LHCb - Kruger2010

18. Additional requirements : Lifetime & tagging • Lifetime and Tagging are key ingredients for time dependent and Bhh Lifetime resolution of 77fs (worse than expected) Recent improvements obtained Tagging performance studies under progress Hadronic B decays @ LHCb - Kruger2010

19. Charmless diagrams Hadronic B decays @ LHCb - Kruger2010

20. ~35pb-1 Hadronic B decays @ LHCb - Kruger2010